A variety of hydrocarbon exploration and other applications involve the use of cables and hoses. The cables and hoses may be employed to provide a link between an underwater or subterranean hydrocarbon environment and a surface location. Operators of hydrocarbon application equipment may be positioned at the surface location. From this location, hydrocarbon tools therebelow may be directed and serviced through the noted hydrocarbon application cables and hoses. Examples of hydrocarbon application hoses in particular may include seismic gun hoses for carrying pressurized air, drilling hoses for transfer of cuttings and drilling fluid, and even coiled tubing for delivering pressurized fluid and tools to a downhole environment.
Hydrocarbon application hoses such as those noted above generally include an inner core of a polymer such as nylon or polytetrafluoroethylene (PTFE) that is surrounded by a reinforcing braided or served stress member, that is, one which is cabled or wrapped. A jacket will also generally be employed encasing such hose components and providing the outer surface of the hose. The reinforcing stress member may be an aramid fiber such as Kevlar™ or other suitable material constructed to help prevent blowout of the hose. That is, for many hydrocarbon applications, pressurized fluid or air may be driven through the hose. Thus, a reinforcing stress member may be employed to help ensure that the pressure driven through the hose does not lead to blowout of the hose which could render it ineffective. Blowout may also render any hydrocarbon equipment or tools coupled to the hose susceptible to damaging environmental conditions surrounding the hose. Thus, effective reinforcement may be critical to the operation of a hydrocarbon hose.
As indicated, the reinforcing member is often a Kevlar™ braid surrounding the core of the hose. Kevlar™ is a fairly lightweight and flexible material. It is also a strong material with a strength-to-weight ratio that is about 5 times stronger than steel on an equal weight basis. Thus, while providing a degree of flexibility it is also particularly well suited to help avoid blowout of a hydrocarbon application hose when extreme pressures are driven through the core of the hose. While the reinforcing member may adequately avoid blowout of the hose, its flexible nature fails to help avoid compression of the hose, for example when directed through a high pressure differential environment. Therefore, the jacket of the hydrocarbon application hose is often of a stiffer material able to withstand high differential pressures while better avoiding collapse and deformation.
Where the hydrocarbon application is a coiled tubing application, a stainless steel outermost jacket may be employed to ensure that the coiled tubing hose is able to adequately withstand high downhole differential pressures without significant collapse or deformation. However, such a stainless steel jacket leaves the coiled tubing hose prone to fatigue over time as it is repeatedly spooled into and out of a well, undergoing plastic deformation as it is straightened and wound over and over. The likelihood of this fatigue resulting in rupture of the hose increases as the amount of deformation increases, for example as the overall size of the hose increases in terms of its diameter. Thus, the outer diameter of the coiled tubing hose may be limited, generally, to less than about 1.5 inches.
In addition to concern over fatigue from the employment of a metal or other relatively inflexible jacket, there are drawbacks to the use of aramid and other porous material fibers to make up the reinforcing member. For example, a Kevlar yarn, comprised of many thousands of small circular fibers, in particular is a very porous element. Therefore, a significant amount of air is generally trapped within the layer of Kevlar reinforcing member. As a result, any breakdown in the jacket material leaves the entire hose immediately vulnerable to collapse when present within a high pressure differential environment. That is, once leakage of high differential pressure fluid or air traverses the jacket, a conventional porous aramid fiber reinforcing member is unable to withstand compressive forces exerted thereon. The hydrocarbon application hose thus collapses.
Unfortunately, there is presently no adequate manner of eliminating the porosity of aramid fiber bundles in order to provide an added or alternate line of defense to the hose when subjected to a high pressure differential environment. Kevlar™, for example, is a highly finished material that generally includes slick and oily filament surfaces rendering it difficult to fill or otherwise eliminate its porosity. Alternatively, where metal armor or wire material is employed as a reinforcing member it is subjected to processing conditions that render it brittle and often of reduced effectiveness in preventing hose blowout. That is, the metal reinforcing member may be integrated into the core material of the hose to eliminate porosity. However, conditions under which the metal is subjected in order to achieve this integration are likely to leave the metal brittle and ineffective.